Security guard forces have long been employed to patrol and protect property against unauthorized intrusion and vandalism. Such forces are common in large industrial complexes housing valuable equipment, inventory, or sensitive information. These complexes include, for example, store rooms, computer rooms, warehouses, manufacturing facilities, office buildings, military bases, department stores and the like. Prior to the introduction of portable two-way radios, such complexes would usually be patrolled by a team of guards with each guard periodically patrolling a designated area of the complex and returning to a central station to report. Obviously, this left most areas of the complex unattended for long periods of time between patrols.
With the introduction of portable two-way radios, each guard of a team could be stationed permanently in his designated area and could report in periodically to a central station via radio. He could also receive instructions via radio from the central dispatcher so that he could be advised quickly and efficiently of a change in his assignment or of an unusual or threatening situation. While such a system is an improvement over roving patrols, it is still subject to numerous inherent problems. The guards, for example, being human, are subject to inattention and can sometimes be evaded by a clever intruder. This is particularly true in situations where little or no activity over long periods of time can lead to extreme boredom and fatigue among the guards. Probably the most serious problem with posted human sentries is the extremely high cost in salaries and benefits of maintaining the necessarily large security force. Further, frequent turnover among security guards can lead to high training costs and reduced overall efficiency.
In recent years, electronic security systems have found widespread use as an adjunct to traditional radio dispatched security guard forces. Such systems can include passive infrared or heat sensors mounted in designated areas of a guarded complex and positioned to detect the presence of a person within the area. Upon such detection, the sensor, which is usually hard wired to a central control, signals the central control, which can emit a visual or audible signal indicating that an intruder has been detected.
Such security systems have allowed reduction in the number of persons required to guard a complex. Further, they are not subject to boredom, fatigue and evasion as human sentries can be. However, these motion detecting security systems are relatively simple, are not generally portable or easily adaptable to changing requirements, and convey no useful information in addition to a simple signal that a detection has been made. Accordingly, a guard responding to a detection must enter the monitored area with little or no information about where in the area the intruder was detected or how he may have been moving within the area.
The present inventor addressed these and other deficiencies in the art by providing an infrared sentry with voiced radio dispatched alarms, as described in U.S. Pat. No. 5,283,549. This device broadcasts radio dispatch messages when an alarm is detected. While the solution provided an excellent solution at the time, additional challenges must be addressed.
Over the past several years, police band radios have become significantly more complex and expensive. Thus, the security units, each of which include a radio, have also become significantly more expensive. Therefore, many police departments are not able to buy the quantity of security units they desire due to budgetary constraints.
Additionally, numerous other industries desire to economically monitor buildings and equipment in remote locations. For example, a information technology support company tasked with maintaining server computers located at its customers' facilities, may desire notification if the server is moved or overheats. Therefore, it would be desirable to provide a system capable of monitoring such equipment and/or facilities and broadcasting an event message to personnel responsible for maintaining the equipment when necessary.
Accordingly, there is a need in the art for a low cost portable monitoring system. Additionally, there is a need in the art for a portable monitoring system that does not require a dispatch radio to be installed in each remote unit. Further, there is a need in the art for a monitoring system in which a single radio device can service multiple remote monitoring stations. Further, there is a need in the art for a monitoring system that can receive event messages from a variety of remote monitor devices and broadcast an event message.